In the past, considerable attention has been given to the problem of locking windows that are purposely left partially open for ventilation.
Various systems have been proposed, in one a vertical tube receives a threaded shaft and a nut on the threaded shaft prevents excessive telescoping together of the shaft and tube to limit the opening of the window, but the brackets proposed were such as to permit the entire telescoping assembly to be moved horizontally inward from the window for easy removal from the brackets by a person wanting to open the window in case of fire.
However, such an ease of horizontal removal also permits a burglar to push the telescoping assembly inward and, therefore, out of the way and out of action so he can enter easily. Because of this, a complicated and costly and bulky and unsightly alarm system was needed to further work with the telescoping system.
However, it is believed that a burglar could not so quickly see this possibility and would also find that he would be making some noise in the process of doing this from the outside. Burglars are reluctant to enter a house while making noise which is why burglars tend to avoid just breaking the glass and unlocking whatever locks there are that way.
Some have proposed attaching the telescoping member to the top of the outer and upper sash by means of a screw, but yet simply allowing the lower end of the telescoping assembly to be rested on but not screwed into the top of the lower sash. This would permit a burglar to insert a tool through the ventilation opening under the lower sash, the tool being especially proportioned to reach up and hook behind the lower end of the telescoping assembly so that the burglar could flip it inward off of the top of the lower sash and thereby enter without breaking glass.
Other proposals have had no attachment to the window frame itself. It is an object of this invention to provide an upper mounting bracket which attaches not only to the top of the upper sash, but also to the window frame itself so that the upper window sash cannot be lowered by a burglar for the purpose of inserting his hands and a screw-driver through that upper opening so as to unscrew the upper mounting bracket.
Some have proposed the placing of a telescoping assembly at the center of a window, but there it obstructs vision as one looks out through the window.